By determining and visualizing a radio standard of a radio signal that travels in the air in a local system and other systems, it is possible to estimate the state of radio interference with respect to a desired wave of the local system. Accordingly, it is possible to identify the standards of other systems which act as an interference source to the local system and to take appropriate measures against the radio interference. For example, various systems such as LoRa, Sigfox, Wi-SUN, and RFID (Radio Frequency IDentification) of LPWA (Low Power Wide Area) co-exist in a subgiga band.
A visualization apparatus that visualizes radio standards measures a bandwidth of a radio signal of each system using a spectrum and performs a primary process for roughly determining a standard according to the bandwidth. Thereafter, the visualization apparatus performs a secondary process for determining the radio standard with high accuracy using raw data of a baseband (BB) signal of the radio signal to obtain a band occupation state of each radio standard. The secondary process has higher analysis accuracy and lower analysis speed than the primary process. Through these two processes, it is possible to determine the radio standards at a high speed and with high accuracy.
As related art, there is a technique for analyzing, for example, a center frequency and a bandwidth by the spectral analysis of a radio packet in the primary process on the assumption that a pulse area of the horizontal axis (bandwidth) and the vertical axis (pulse duration) on a spectrum is “rectangular” (see, e.g., Japanese National Publication of International Patent Application No. 2005-523616). There is also a technique for adjusting a frequency resolution/a time resolution in an ultrasonic diagnostic apparatus (see, e.g., Japanese Laid-open Patent Publication No. 11-285495).